Field of the Invention
The present invention relates to a measurement system.
Description of the Background Art
Known from WO 2010/060607 A2, which corresponds to U.S. Pat. No. 8,680,847, which is incorporated herein by reference, is an IC package with a semiconductor chip with an integrated circuit and an integrated magnetic sensor. Spaced apart from the package of the semiconductor chip is a permanent magnet whose magnetic flux penetrates the sensor. If an object to be measured approaches the head end of the semiconductor chip, the magnetic flux density through the sensor changes.
Integrated magnetic Hall effect sensors in which a permanent magnet is incorporated into the IC package are known from U.S. Pat. No. 7,250,760 B2. In this design, the Hall effect sensors are arranged relative to the field of the permanent magnet in such a manner that a Hall voltage is generated without the influence of external fields.
Known from DE 698 27 559 T2, which corresponds to U.S. Pat. No. 5,963,028, is a package for a magnetic field sensor. Conventionally, an air gap is defined as the distance between the exciter and the outer surface of the package containing a measuring element of the magnetic field sensor. An “effective air gap” may be described as the distance between the exciter and the measuring element itself. Magnetic field sensors typically include a permanent magnet and a measuring element that is encapsulated in a package. However, this type of packaging is unsuited for harsh environments, particularly that of an automobile. Accordingly, such packaged measuring elements are further enclosed in an additional housing (overmold), which affords protection from moisture and dirt. This leads to a decrease in the peak magnetic field strength as a tooth passes through the magnetic field in proximity to the measuring element. In DE 698 27 559 T2, it is desirable to have the measuring element as close as possible to the magnet, since the magnetic field decreases as a function of the air gap. A short distance allows the use of a small magnet with a lower energy product.
A 3D magnetic sensor is known from DE 10 2012 203 001 A1, which corresponds to US 20120217960. The magnetic field sensor has a low-profile soft magnetic body arranged on a surface of a substrate that has a magnetic sensor array with a plurality of spatially diverse magnetic sensor elements that are arranged in a predetermined configuration. In the presence of an external magnetic field, the low-profile soft magnetic body is magnetized in order to generate a reactive magnetic field. The plurality of magnetic sensor elements are each configured to measure a magnetic field value of a superposition of the external magnetic field and the reactive magnetic field along a first axis (for example, a z-axis), resulting in a plurality of spatially diverse measurements of the magnetic field component along the first axis. The plurality of spatially diverse measurements can be used to calculate magnetic field components of the external magnetic field along a plurality of axes (for example, x-axis, y-axis, and z-axis).